Collaborative Research: Conformational Equilibria of Biologically Important Saccharides and Related Biomolecules

凭借该奖项，化学部的生命过程化学项目正在资助圣母大学的 Anthony Serianni 博士和佐治亚大学的 Robert Woods 博士研究溶液中糖分子或糖类的三维特性。嵌入细胞表面的糖在生物学中发挥着关键作用。 在人类中，它们附着在可溶性和膜相关的蛋白质和脂质上，其生物学作用包括细胞间识别和免疫识别。虽然众所周知，糖的结构特性与其生物功能相关，但通过实验方法在溶液中分配这些结构细节仍然很困难。这种困难导致严重依赖理论方法来分配结构，尽管这些方法很难通过实验验证。该项目旨在通过开发和应用一种新的实验技术来确定溶液中糖类中柔性结构域的群体，包括将它们在聚合物中连接在一起的键以及将它们连接到其他生物分子的键，从而解决这个问题。获得的实验衍生信息可以与从理论获得的信息进行比较，以测试和/或验证后者。对实验和计算科学感兴趣并具有专业知识的高级研究人员、研究生和本科生合作实现该项目的目标。这项工作为确定分子结构提供了有价值的新工具，可普遍应用于溶液中的任何生物分子，包括蛋白质和核酸。该研究项目使用稳定同位素标记的寡糖和糖肽、核磁共振（NMR）自旋耦合、密度泛函理论计算、循环统计和X射线晶体学来确定溶液中寡糖柔性结构域的构象群。这种实验方法是可行的，因为糖类含有多个 NMR 自旋耦合，这些自旋耦合报告相同的构象域，允许定量处理产生连续的单态和多态群体模型。一旦给定的结构域被参数化（例如，O-或N-糖苷键），就可以在不同的结构背景下研究其构象特性，以确定其构象适应环境线索的程度。将实验模型与分子动力学模拟获得的模型进行比较，以验证后者。这项工作带来了基于实验的寡糖中 O-糖苷键的新构象分类，并加深了对影响溶液中寡糖构象的多种因素的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Anthony Serianni from the University of Notre Dame and Dr. Robert Woods from the University of Georgia to investigate the three-dimensional properties of sugar molecules, or saccharides, in solution. Saccharides embedded in cell surfaces play critical roles in biology. In humans, they are attached to soluble and membrane associated proteins and lipids, and their biological roles include cell-to-cell and immune recognition. While it is well known that the structural properties of saccharides correlate with their biological functions, it remains difficult to assign these structural details in solution by experimental methods. This difficulty has led to a heavy reliance on theoretical methods to assign structures even though these methods have been difficult to validate experimentally. This project aims to solve this problem by developing and applying a new experimental technique to determine populations of flexible domains in saccharides in solution, including the linkages connecting them together in polymers and linkages that attach them to other biomolecules. The experiment-derived information obtained can be compared to what is obtained from theory to test and/or validate the latter. Senior researchers, graduate students and undergraduates with interests and expertise in experimental and computational science collaborate to achieve the objectives of the project. This work provides valuable new tools to determine molecular structure that can be generally applied to any biomolecule in solution, including proteins and nucleic acids.This research project uses stable isotopically labeled oligosaccharides and glycopeptides, nuclear magnetic resonance (NMR) spin-couplings, density functional theory calculations, circular statistics and X-ray crystallography to determine conformational populations of the flexible domains of oligosaccharides in solution. This experimental approach is possible because saccharides contain multiple NMR spin-couplings that report on the same conformational domain, allowing quantitative treatments that yield continuous single- and multi-state populational models. Once a given domain is parameterized (e.g., O- or N-glycosidic linkage), its conformational properties can be investigated in different structural contexts to determine the degree to which it adapts conformationally to environmental cues. Experimental models are compared to those obtained from molecular dynamics simulations to validate the latter. This work leads to new experiment-based conformational classifications of O-glycosidic linkages in oligosaccharides, and to a deeper understanding of the multiple factors that influence oligosaccharide conformation in solution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.